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GrahameKing
Aug 23, 2006
The following code demonstrates one way of converting any number to standard scientific notation. This code is from newsletter 139, posted here by the author. [[code]] ' test program for scientific notation function by Grahame King - released to public domain August 2006 a=1 while a<>0 input "test number ="; a a$ = str$(a) print "test number as string = "+a$ print "test number in scientific notation = "+ScNotation$(a) wend end function ScNotation$(numin) ' function to express a number as a string in 'scientific notation" if numin = 0 then ScNotation$ = "0" : exit function ' separate number into sign, significant numeric part (mantissa), and exponent ' first extract the sign absNumIn = abs(numin) sgnNumIn = absNumIn/numin if sgnNumIn>0 then sgnNumIn$ = "" else sgnNumIn$ = "-" end if ' represent unsigned number as a string using str$ absNumIn$ = str$(absNumIn) ' find the "e" in case LB has already put it in a form with an exponent inde = instr(absNumIn$,"e") if inde>0 then expon = val(mid$(absNumIn$,inde+1)) mantissa$ = mid$(absNumIn$,1,inde-1) else expon = 0 mantissa$ = absNumIn$ end if ' move the decimal point in the old mantissa so that there is just one nonzero digit in front of it ' and adjust the exponent accordingly ' start by finding the decimal point and breaking mantissa into its whole part and fractional part indDot = instr(mantissa$,".") if indDot = 0 then ' for integers indDot = len(mantissa$) whole$ = mantissa$ fract$ = "" else whole$ = mid$(mantissa$,1,indDot-1) fract$ = mid$(mantissa$,indDot+1) end if while val(whole$) > 9 ' to move decimal point to the left if necessary indDot = indDot-1 fract$ = right$(whole$,1)+fract$ ' add the last digit from the whole number part to the beginning of fract$ whole$ = left$(whole$,len(whole$)-1) ' and then remove that digit from the whole$ expon = expon+1 ' adjust exponent to keep the net result correct wend while val(whole$) <= 0 ' to move decimal point to the right if necessary indDot = indDot+1 whole$ = whole$+left$(fract$,1) ' add the first digit of fractional part to the whole number part fract$ = mid$(fract$,2) ' and then remove that digit from the beginning of the fractional part expon = expon-1 ' adjust exponent to keep the net result correct wend ' build Scientific Notation string from the three parts - sign, new mantissa and new exponent ScNotation$ = sgnNumIn$+str$(val(whole$))+"."+fract$+"e"+str$(expon) end function [[code]]